Accurate industrial temperature measurements with loop-powered transmitter

March 03, 2014 // By Graham Prophet
Taking power from a 4-20-mA signalling loop, and transmitting with the HART Protocol, Maxim Integrated’s Novato reference design accurately measures and transmits industrial temperatures over -200°C to +850°C range with better than ±0.1% accuracy.

Temperature is among the most widely measured parameters in industrial process control and automation applications. The Novato reference design transmits temperature measurements from remote sensors to the central control unit over a 4–20mA current-loop using the highway addressable remote transducer (HART) communication protocol. This smart transmitter enables low-power temperature measurement from -200°C to +850°C with accuracy better than ±0.1% or ±1.0°C. Novato's flexible design supports 2-, 3-, or 4-wire resistance temperature detector (RTD) sensor inputs and works with any type of RTDs, from PT100 to PT1000, making it ideal for a wide variety of industrial applications. A low power design, it consumes less than 3.2mA.

HART Communication Protocol: the HART functions set is developed by AB Tech Solution, Westford, MA, an engineering firm specialised in product development services for industrial automation applications. The HART stack for Novato runs on the Renesas RL78/G13 microcontroller and supports all universal and common practice commands.

Pricing starts at $99; the design fits into a DIN size B head-mounting enclosure (< 40mm diameter) to meet field sensor needs.

Maxim Integrated;